


Naughty Shape Changing

by MaggieMaybe160



Category: The Infernal Devices Series - Cassandra Clare
Genre: Bodyswap, Masturbation, Mild Smut, Other, Smut, Sneaking Around
Language: English
Status: Completed
Published: 2018-09-28
Updated: 2018-09-28
Packaged: 2019-07-18 18:20:22
Rating: Mature
Warnings: Creator Chose Not To Use Archive Warnings
Chapters: 1
Words: 1,458
Publisher: archiveofourown.org
Story URL: https://archiveofourown.org/works/16124123
Author URL: https://archiveofourown.org/users/MaggieMaybe160/pseuds/MaggieMaybe160
Summary: Tessa has the opportunity to shape change into Will Herondale when he leaves the Institute in a hurry.





	Naughty Shape Changing

Tessa knew she had time today. At breakfast Charlotte had dispatched Will and Jem on a hunt with herself and Henry paying a visit to another shadowhunter family, Tessa couldn’t remember who. Jessamine would likely keep to herself as she usually did and the servants of the London Institute all had their jobs. 

Tessa looked down the hall either way before quickly closing her door and locking it. She knew what she was doing was wrong, but she was curious. Ever since she’d met the mysterious Will Herondale, she’d wanted to know everything she could about him. The easiest way to do that it seemed would be to change into him. She’d been stealthily stealing his clothes from the laundry room every time she was down there with Sophie. He’d noticed of course, bringing up that he couldn’t find his shirt at breakfast three days in a row. “Are you sure you didn’t leave it with Six Fingered Nigel, again?” Jem had asked with a small smile. 

Tessa opened her wardrobe and pried open the back panel, revealing the small secret space that she’d been stashing Will’s outfit in. After changing into his clothes, Tessa sat down at her vanity table and took a dagger out of Will’s pants pocket. She met her own eyes in the mirror. “Talk me out of it.” She whispered to her reflection. She looked back down at the dagger and tightened her grip before closing her eyes to feel for Will in his dagger. 

As she reached into it she felt the cool wash of the change fall over her like black water. Every time she had changed she had been able to easily pull memories and thoughts but as she emerged as Will, she felt the guards in his mind. She sifted through what was easy to find and found memories of fighting side by side with Jem, walking alone in the dark London streets, and casual, careful hands picking up books in the library. Tessa heard her own voice in his head, “Hell is cold.” 

Finally, Tessa willed herself to open her eyes and saw the beautiful face that she couldn’t stop herself from thinking about. Will’s dark blue eyes looked less guarded when she wore them. His dark hair was curled at his neck and she reached up a pale hand to touch the curl lightly. Looking down she could see the dark swirls of his Marks through the undershirt she was wearing. 

Tessa went to her door and unlocked it, looking outside of her room through a slit to make sure no one was there. She couldn’t stay in her room for fear that Sophie would turn up and be suspicious as to why the door was locked. She slipped out and made her way quickly to the library to find Will’s favorite books with his mind to guide her. Using his memory, she knew the entire layout of the Institute like a map. When she got to the library she went to the back of the room and began trailing Will’s fingers along the spines of books as she had just seen him do in her mind.  _ A Tale of Two Cities _ Will’s thoughts urged her. 

“That’s impossible. He’s told me how he despises that book.” Tessa whispered in Will’s voice. His thoughts insisted still.  _ A Tale of Two Cities. _ Tessa plucked it off the shelf even though she had returned it to this shelf only a week ago. She left the library with the book and made her way back to her room. She watched Will’s long legs as she walked. She slipped into not her room. Will’s room surrounded her. Books were piled everywhere and his clothes were thrown over the floor and furniture.  _ No wonder no one was surprised that Will couldn’t find his shirt. _ Tessa sat down on a chair in front of a mirror that was almost obscured with the piles of books that Will had left there. 

She looked down again at the Marks under his shirt and told herself silently that she was just curious to see what the Marks looked like. She pulled his shirt off and ran his fingers over the jet black swirls that danced on his pale skin. She thought of their kiss in the attic and how it tasted: so much of Will and the hint of vampire blood. She thought of how feverish his skin had been to touch and how desperate their kiss was. 

Tessa ran Will’s fingertips over his lips as she looked in the mirror. Her other hand had found its way to the top of Will’s pants. Will’s cheeks in the mirror were flushed with a deep blush as she thought about what she was doing and what she was thinking of doing. Everything about this was improper. There wasn’t even a precedent for this that Aunt Harriet would have had told Tessa about. Tessa played with the buttons on Will’s pants until finally opening them and kicking the pants to the floor. She closed her eyes and looked back up at the mirror trying not to look back down, embarrassed for both herself and Will that she was even doing this. 

Looking into Will’s deep blue eyes wasn’t helping. The blush in his pale face made his eyes stand out more and his black hair that curled at the ends made her heart race. She reached up with one hand and ran her hand through his hair, closing her eyes and sighing at the touch of it. Her other hand tentatively and blindly trailed over his thigh, pausing at the top. She moved her hand around his stiff erection and let her fingers trail over every inch, shivering as the sensation ran through her. 

Tessa gently circled the shaft in Will’s hand and let Will’s instincts take over. She let out a soft moan in Will’s voice and she bit her lip, sliding her hand and feeling a small sweat rise on her skin. She moved her thumb over the soft, sensitive skin of the tip of Will. Tessa groaned audibly in Will’s deep and now husky voice, turning herself on more. She moved her hand faster, sliding up and down the hard shaft and feeling herself giving in. She moaned a final time as warm liquid spilled from the top onto her hand. She stopped, breathing hard, and stared into the mirror in slight horror at what she’d just done. 

She still didn’t want to look down even after she’d already crossed a line that couldn’t be uncrossed. She looked around frantically for something to clean up and grabbed the nearest towel which was next to Will’s washstand. She mopped off the sticky fluid from Will’s hands and pulled Will’s pants back on in a hurry. She caught his reflection in the mirror. The blush was still high in his cheeks and her hands had messed up his hair in a sexy way, making her heart pause from its racing beat. 

_ I need to get back to my room. _ Tessa thought as she grabbed Will’s shirt from the floor. She combed her fingers through the curly black hair and opened the door to Will’s room quietly. No one was in the hallway. Tessa closed the door and started off down the hall as fast as she could without running or looking suspicious in case Sophie saw. 

“There you are!” Jem’s voice called behind her. Tessa froze and turned around to see Jem quickening his pace to catch up. “I thought you were going to disappear well into the night as usual.” 

“Oh. Uhm.” Tessa didn’t know what to say. Will’s voice wasn’t in her head telling her what to say. 

“Are you okay?” Jem asked, noticing the blush that was still on Will’s face. Tessa looked away quickly. 

“F-Fine.” Tessa scolded herself for stuttering as she tried to think of how to get out of this situation. “Give me a moment.” 

“Alright?” Jem’s look of worry was apparent but Tessa couldn’t care about that right now. She took off down the hall and broke into a run when she was out of Jem’s sight. She made it to her room and slammed the door behind her. 

Tessa let the Change melt off of her and stashed Will’s clothes back in her wardrobe before changing back into the dress she had been wearing at breakfast and slipping her angel necklace back on. Tessa went to the mirror and found her reflection was her own. Her cheeks were bright with the blush that had belonged on Will’s face moments before. She closed her eyes and willed herself not to think of it again before going back out into the hallway. 


End file.
